Add and Subtract Within 100: 9 + 15

🌍 Where you'd use this: Every time you check the score, count change, or figure out how long until something — that's this.

🤯 Fun fact: 🤯 The number 0 is younger than you think. People did math for thousands of years before they invented zero.

🏆 Try this week: Time yourself on 10 mental math problems before bed for 5 days. Track your speed.

👨‍👩‍👧 At dinner: “What's the fastest way you can think of to solve 27 + 18? No paper.”